This study reports that in rat skeletal muscle the proteins specifically responsible for mitochondrial dynamics, mitofusin-2 (MFN2) and mitochondrial dynamics protein 49 (MiD49), are higher (p < 0.05) in oxidative soleus (SOL) muscle compared with predominantly glycolytic extensor digitorum longus (EDL) muscle, but not seen for optic atrophy 1 (OPA1; p = 0.06). Markers of mitochondrial content, complex I component, NADH:Ubiquinone oxidoreductase subunit A9 (NDUFA9) and complex IV protein, cytochrome C oxidase subunit IV (COXIV; p < 0.05) were also higher in SOL compared with EDL muscle; however, there was no difference in mitochondrial content between muscles, as measured using a citrate synthase assay (p > 0.05). SOL and EDL muscles were compared between age-matched sedentary rats that were housed individually with (RUN) or without (SED) free-access to a running wheel for 12 weeks and showed no change in mitochondrial content, as examined by the abundances of NDUFA9 and COXIV proteins, as well as citrate synthase activity, in either muscle (p > 0.05). Compared to SED animals, MiD49 and OPA1 were not different in either EDL or SOL muscles, and MFN2 was higher in SOL muscles from RUN rats (p < 0.05). Overall, these findings reveal that voluntary wheel running is an insufficient stimulus to result in a significantly higher abundance of most markers of mitochondrial content or dynamics, and it is likely that a greater stimulus, such as either adding resistance to the wheel or an increase in running volume by using a treadmill, is required for mitochondrial adaptation in rat skeletal muscle.

中文翻译：

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随意轮运行对大鼠骨骼肌线粒体含量和动力学的影响。

这项研究报告说，在大鼠骨骼肌中，与主要糖酵解伸肌相比，氧化比目鱼肌 (SOL) 肌肉中专门负责线粒体动力学的蛋白质 mitofusin-2 (MFN2) 和线粒体动力学蛋白 49 (MiD49) 更高 (p < 0.05)指长肌 (EDL) 肌肉，但未见于视神经萎缩 1 (OPA1；p = 0.06)。与 EDL 肌肉相比，SOL 中的线粒体含量、复合物 I 成分、NADH：泛醌氧化还原酶亚基 A9（NDUFA9）和复合物 IV 蛋白、细胞色素 C 氧化酶亚基 IV（COXIV；p < 0.05）的标志物也更高；然而，使用柠檬酸合酶测定法测量的肌肉之间的线粒体含量没有差异（p > 0.05）。SOL 和 EDL 肌肉在年龄匹配的久坐大鼠之间进行比较，这些大鼠单独饲养 (RUN) 或不 (SED) 自由进入跑步轮 12 周，并且线粒体含量没有变化，如通过 NDUFA9 的丰度检查和 COXIV 蛋白，以及柠檬酸合酶活性，在任一肌肉中（p > 0.05）。与 SED 动物相比，MiD49 和 OPA1 在 EDL 或 SOL 肌肉中没有差异，而 RUN 大鼠的 SOL 肌肉中的 MFN2 更高（p < 0.05）。总体而言，这些研究结果表明，自主轮跑是一种不足以导致线粒体含量或动力学的大多数标志物显着更高丰度的刺激，并且可能是更大的刺激，例如增加轮子的阻力或增加使用跑步机的跑步量，